Delcatty/Magneton Question?

Ok 1st Delcatty's Poke Power states
Energy Draw:Once during your ( before your attack), you may discard 1 energy card from your hand. Then draw up to 3 cards from your deck.

my question is can you discard the energy and not draw becuz it states ( draw up to 3 cards )

2nd Magenetons poke power
Magnetic Field: Once during your turn ( before your attack ), if you have basic energy cards in your discard pile, you may discard any 1 card from your hand. Then search for ( up to 2 basic energy cards ) from your discard pile..

So my question is.....are you able to dicard the required cards in order to use the 1st part of the effect and not the second becuz it states ( up to ) in the statment...for ex. on delcatty can i disacard the energy to draw 0 cards and on magneton can i discard a card to return 0 energy back to my hand...
The reason i asked this is i play a blaziken deck and there are time i want energy in the discard but i dont want to draw or return energies to my hand.